A novel technique to decouple electrical and thermal effects in SOA limitation of power LDMOSFET

This letter reports a novel technique to isolate thermal and electrical failure mechanisms in a power LDMOSFET device by deactivating the parasitic bipolar transistor while maintaining the MOS gate control. It is shown that the energy capability of the device remains constant as a function of the drain voltage in the event of a purely thermal failure, whereas the standard device shows a decrease in energy capability indicating electrothermal coupling. Nevertheless, the standard device energy capability is close to that obtained in the case of pure thermal failure, indicating that the thermal phenomenon dominates in determining the device failure and that electrical effects, though present, only minutely influence the device failure.